High pressure separation device

Abstract

A device for separating a high pressure polyphase mixture consisting of a gas charged with liquid particles, and particularly a mixture of ethylene and polyethylene, which comprises a cylindrical vertical enclosure into which extends an inlet means for supplying the mixture thereto and which is provided at its lower end with an outlet for discharging separated liquids; a vertical cyclone in communication with the enclosure for receiving separated gases therefrom and having an outlet at its upper end for discharging gases separated in the cyclone and a liquid outlet at its lower end for discharging separated liquids therefrom; and an ejector comprising a nozzle, through which the polyphase mixture is fed, a mixing zone connected to the liquid outlet of the cyclone and a diffuser section for reducing the speed of the resultant mixture and being connected to the inlet means for supplying the polyphase mixture to the enclosure.

What is claimed is: 
     
       1. A device for separating a high pressure polyphase mixture consisting of a gas charged with liquid particles, said device comprising: (a) vertical cylindrical separator enclosure means for expanding said polyphase mixture and separating said mixture into a gas and a liquid phase, said means having an outlet at its lower end for discharging separated liquids therefrom;   (b) vertical cyclone means in communication with said enclosure means for receiving separated gases therefrom, said cyclone means having a gas outlet at its upper end for discharging separated gases therefrom and a liquid outlet at its lower end for discharging separated liquids therefrom; and   (c) means for supplying the polyphase mixture to said vertical enclosure means, said means comprising   (i) an ejector comprising a nozzle through which the polyphase mixture is fed to increase its speed, a mixing zone connected to the liquid outlet of the cyclone means for entraining the separated liquids from said cyclone means in the polyphase mixture, and a diffuser section for reducing the speed of the resultant mixture, and   (ii) means connected to said diffuser section and opening into said enclosure means.   
     
     
       2. The device of claim 1, wherein said means connected to said diffuser section and opening into said enclosure means is positioned and constructed to discharge said mixture into said enclosure means in a direction substantially parallel to the axis of said enclosure means. 
     
     
       3. The device of claim 2, wherein said means connected to said diffuser section and opening into said enclosure means comprises a tube that extends into said enclosure means and terminates in a downwardly opening cone located in the upper portion of said cylindrical enclosure means, the angle of the apex of said cone being from 4 to 30 degrees. 
     
     
       4. The device of claim 2, wherein the means connected to said diffuser section and opening into said enclosure means comprises a tube that extends into and parallel to the axis of said cylindrical enclosure means, the end of said tube being bent downwardly in the upper portion of the cylindrical enclosure means toward the bottom and forming, with the vertical in the downward direction, and angle that is less than or equal to 80°. 
     
     
       5. The device according to any one of claims 1 to 4 wherein said cyclone means and said ejector are both located inside said enclosure means. 
     
     
       6. The device of claim 5, wherein said communication between said cyclone means and said enclosure means includes, in an upper part of said cyclone means, an inlet orifice for admitting the gases separated in said enclosure means. 
     
     
       7. The device of claim 6, wherein the cross-section of said inlet orifice is constructed so as to obtain an entry speed of the gases into said cyclone means of between 0.5 and 20 m/second. 
     
     
       8. The device of claim 6, wherein the liquid outlet at the lower end of the cyclone means is connected to said mixing zone of said ejector by a single conduit. 
     
     
       9. The device according to any one of claims 1 to 4, wherein said cyclone means and said ejector are both located outside said enclosure means. 
     
     
       10. The device of claim 9, wherein said communication between said cyclone means and said enclosure means is an outlet in the upper end of said enclosure means for receiving the gases separated in said enclosure means and conveying them to said cyclone means. 
     
     
       11. The device of claim 10, further comprising a valve connecting said liquid outlet in said cyclone means to said mixing zone of said ejector. 
     
     
       12. The device of claim 11, further comprising, between said valve and said ejector, means for supplying gas to the liquids separated in said cyclone means.